Degrading and removing harmful compounds by the use of semiconductor photocatalysts has been testified to be and effective and attractive green technique in wastewater treatment. Herein, carbon dots sensitized BiOI with highly exposed {001} facets has been prepared and used to study the photocatalytic degradation of methyl orange (MO). Due to the improved charge separation, transfer, and optical absorption, the photocatalytic performance for methyl orange degradation of the carbon dots/{001} BiOI nanosheets is 4 times higher than that of the {001} BiOI nanosheets under visible light irradiation. Additionally, the carbon dots/{001} BiOI nanosheets also have superior stability after 5 cyclings.